Manufacture of oxalates.



D. STRAUSS.

MANUFACTURE OF OXALATES.

APPLICATION FILED APR.11,1910.

1,038,985,, Patented Sept. 17, 1912.

I 1 i f UNITED STATES PATENT oEEIoE.

DAVID STRAUSS, 0F BASEL, SWITZERLAND, ASSIGNOR TO SOCIETY OF CHEMICALINDUSTRY IN BASLE, OI BASEL, SWITZERLAND.

MANUFACTURE OF OXAI'JATES.

Specification of Letters Patent.

Patented Sept. 17, 1912".

Application filed April 11, 1910. Serial No. 554,808.

To all whom it may concem:

Be it known that I, .DAVID STRAUSS, chemist, a subject of-the King ofPrussia, and resident of Basel, Switzerland, have invented a new anduseful Process for the Manufacture of Oxalates, of which the followingis a full, clear, and exact specification.

As Merz and WVeith have shown (Berliner Berichz e 15, pages 1507 andfollowing) alkali formates may be converted into oxalates by action ofheat, water being eliminated. Yields worthy of consideration could onlybe obtained, however, by operating with-small quantities of formate andby heating to about 420 C. as quickly as possible in a partial vacuum.Several varia-v tions have been proposed in order to over.- come thedifliculties which present themselves in the technical application ofMerz and 'Weiths'reaction. Most of these varia-.

tions consist in heating a mixture of the formate with another compound,such-as an alkali carbonate, an alkali oxalate, or a caustic alkali,either in presence or absence of air.

According to the present invention no other substance need be present,nor need air be excluded, for the formate can be converted in a mostsimple manner and approximately quantitatively into oxalate, byintroducing the-formate without any initial admixture and withoutexclusion of air intov a fusion vessel previously heated to atemperature above 400 C., the introduction of the formate and theheating being so con-' weight C having the tendency to hold the lids intheir position, when they are opened. The pan A is surrounded by areceptacle D confining an air bath between itself and the pan A anddisposedabove a series of gas J burnersE, the said receptacle D and gasburners E being contained in the interior of a masonry mass F providedwith the necessary flue for the evacuation of the combustion gases. Thepan A is provided with a tube 'e for the evacuation of the steamandgases resulting from the reaction in the sald pan. A socket Hprovided on the bottom of A and normally closed by a valve K allows toremove from the pan A'the .oxalate produced, at the end of eachoperation.

The lids being opened fromtime to time,

the formate is gradually introduced in the" iron pan A previously heatedto above 400 0., while the stirring device B is in function. A suitabletemperature, for example, will be between 500 C. and 570 C. The quantityof formate to be'heated in one operation depends on the size of theheating pan. Preferably 150-200 kilos of formate may be heated persquare meter of heating surface.

The charging of the formateinto the pan A and the heating of this latterare so controlled that the temperature of the pan can be maintainedabove 400 C. during the whole operation. The conversion into oxalateoccurs very quickly and is finished after 15-30 minutes. The oxalateproduced is in the form of a light powder and through the socket H itcan be removed straightway from the pan for further treatment, which isnot the case when the operation is con ducted in a partial vacuum:

It will be apparent that the present invention presents the advantagesover the known processes for the manufacture of oxalate, that no initialadmixture is necessary and that air need not be excluded. Admixturesgive rise to useless material in the product of the reaction; theproduction of a vacuous chamber causes considerable technicaldifliculties in working on a large scale,

particularly when, as in this case, a gas is liberated by the reaction.

Instead of the heating pan prescribed in the example any other apparatussuitable for the purpose, such as a heated rotating drum with astirrer,'may be used.

What I claim is: The herein described process for the manufacture ofoxalates from formates by introducing alkali formate without an initialadmixture and wlthout exclusion 0 air into a fusion vessel previouslyheated to a temmy name this first day of April, 1910, in the peratureabove 400 0., the introduction of presence of two subscribing Witnesses.

the formate' and the heating being so coni trolled that during thereaction the tem- DAVID STRAUSS 5 perature of the vessel is constantlymain- Witnesses:

*ained above 400? C. GEO. GIIFORD,

In witness whereof I have hereunto signed AMAND BITTER

